Gradio normally creates the temp directory in `pil_to_temp_file()` (https://github.com/gradio-app/gradio/blob/861d752a83da0f95e9f79173069b69eababeed39/gradio/components/base.py#L313) but since the Gradio implementation of `pil_to_temp_file()` is replaced with `save_pil_to_file()`, the Gradio temp directory should also be created by `save_pil_to_file()` when necessary.